Filler over SPI epoxy AFTER 30 days

Just a couple more questions.

What grit sandpaper should I use when sanding the epoxy prior to scuffing. I think it's inevitable that I will be some sand through to bare metal, is that a big problem?

When I reapply epoxy to the entire engine compartment, how many coats should I put on and can I get a satin black finish with the epoxy?

Tex, thanks for all the help.
 
Hey Texasking got a similar question I am stripping in sections and spraying epoxy as I go and I probably wont get to body filler until everything's sanded and epoxied. So if I happen to go outside the 30 day window, now to get a chemical bond adhesion as you explained does the previous epoxy needed to be scuffed, if so with what grit 180?
 
Yep, 180. Red pads for hard to reach areas as well.
To avoid needing to go back and re-sand and re-epoxy before filler, simply do the filler work on the panel and re-prime while it's still within the recoat window, before moving onto the next panel.
 
okay just need something clarified for the sake of lack of knowledge. I am new to doing this the correct way but if I am repairing a certain area on the panel or body on the car, do I just scuff the repair area or the entire panel need to be scuffed fixed and resprayed with epoxy. I know this sounds elementary to a lot of experienced guys out there but I just need a little guidance and I got it from there. Thanks guys
 
When I reapply epoxy to the entire engine compartment, how many coats should I put on and can I get a satin black finish with the epoxy?
2 coats would be my suggestion. I would consider the gloss to be on the shiny side of satin, but it does lose a little gloss as it cures. Let it induce at least the 30 minutes, but longer, even overnight covered, is better. Spray 1 medium wet coat, wait 30 minutes, then spray a nice wet coat. Going through to metal in spots while sanding is not a problem.
 
okay just need something clarified for the sake of lack of knowledge. I am new to doing this the correct way but if I am repairing a certain area on the panel or body on the car, do I just scuff the repair area or the entire panel need to be scuffed fixed and resprayed with epoxy. I know this sounds elementary to a lot of experienced guys out there but I just need a little guidance and I got it from there. Thanks guys
I usually do panels, but if you just want to do a quarter panel, for instance, just make sure you scuff past where the epoxy will be applied.
 
okay, so texasking and all you other guys explained to me why I needed to strip down to bare metal. I working my rooster off getting this done. My plan is to actually strip the car and epoxy and then come back fix areas that needed repair. after car was completely stripped. That was why I asked about going outside the 30 day window. I dont want to get to confused and get side tracked. I am stripping and spraying epoxy in sections. So far I got the roof, both sail panels, trunk and one quarter panel done. So i guess Im about halfway through. So should I continue stripping and applying epoxy and wait to to do body work. any advise or suggestion welcomed.
 
Yep, 180. Red pads for hard to reach areas as well.
To avoid needing to go back and re-sand and re-epoxy before filler, simply do the filler work on the panel and re-prime while it's still within the recoat window, before moving onto the next panel.

Hi crash,

So, it's just 180 and then red scuff pad for hard to reach areas and then you're done, right? Dose this also work when you're re-coating with epoxy alone for the final finish and the 180 scratches with be covered with the epoxy?
 
okay, so texasking and all you other guys explained to me why I needed to strip down to bare metal. I working my rooster off getting this done. My plan is to actually strip the car and epoxy and then come back fix areas that needed repair. after car was completely stripped. That was why I asked about going outside the 30 day window. I dont want to get to confused and get side tracked. I am stripping and spraying epoxy in sections. So far I got the roof, both sail panels, trunk and one quarter panel done. So i guess Im about halfway through. So should I continue stripping and applying epoxy and wait to to do body work. any advise or suggestion welcomed.
Since you are already half way through, just get the rest stripped and in epoxy. After that, pick a panel, block it lightly with 180, reapply 1 coat epoxy and do filler work the next day up to 7 days. Finish that panel and reapply epoxy, 2K, or polyester until it is ready for a final sand. Repeat until you have worked your way around the car. This way keeps you in the epoxy window and lets you concentrate on a smaller area without undo pressure.
 
Hi crash,

So, it's just 180 and then red scuff pad for hard to reach areas and then you're done, right? Dose this also work when you're re-coating with epoxy alone for the final finish and the 180 scratches with be covered with the epoxy?
I'm not sure if I understand you, but generally speaking, you'd want to be in a finer grit of the primer just before paint, say 220 finished with 320.
 
After reading many threats here related to this topic I found this one to be the most appropriate to post my question.

Background:
This is my first time doing any paint or bodywork. I understand and agree with the concept and theory behind applying filler over epoxy within the 7 day recoat window. Since I am inexperienced, I will most likely move way slower than most of you.

Is there a difference in adhesion between the two methods outlined below?
- Apply epoxy to bear sanded metal, apply filler over fresh, unsanded epoxy within the 7 day recoat window?
or
- Apply epoxy to bear sanded metal, after 7 days, sand the epoxy with 180 or red scotch-bright, reapply one or two coats of fresh epoxy in sections, and then apply filler over the fresh epoxy section.

I am willing to do it the right way, however, the second option will be easier at my current skill level. At the moment the car is in bare metal and I would like to get it sealed/protected sooner rather than later.

Thanks,
Emil
 
Always use 180 to sand epoxy where you are going to use filler. Never scotch Brite pads because it's not deep enough. Similar to Velcro. If one side isn't course enough it's not going to bond together. Years ago I read of an experiment done by a company, don't remember which one, that showed 180 scratch had the best adhesion for filler that had been applied over it.
 
That makes me feel better. Definitely sanded with 80 prior to applying the filler. I’ve been sick to my stomach thinking about it all day...
I used to put filler over older epoxy all the time when I was doing my first project. Like Barry said, as long as it feathers out at the edges, it’s fine and is adhering good.

That was in 2010 and it still looks perfect. Of course I did sand the epoxy first.

Today I do try to get filler on fresh epoxy however, as best practice. But don’t make yourself sick over it, if you sanded failure is not imminent with what you already have.
 
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